Caracterização genética do vírus Chikungunya circulante no Estado do Rio Grande do Norte

Abstract

Chikungunya fever is a febrile syndrome with severe debilitating arthralgia, which may progress to atypical cases, such as neurological and mucocutaneous manifestations. It is usually transmitted by mosquitoes of the genus Aedes. The etiological agent is the Chikungunya virus (CHIKV) that belongs to the family Togaviridae and to the genus Alphavirus. Until recently this disease was neglected in Brazil, but with the epidemic outbreak that occurred in the year 2016, this arbovirose has become a challenge for public health. The objective of the present study was to perform the genetic characterization of the CHIKV identified in the State of Rio Grande do Norte (RN), in the biennium 2016-2017. A total of 10 serum samples, cerebrospinal fluid (CSF) or blister samples were analyzed by the qRT-PCR methodology for CHIKV detection and all were positive. Phylogeny and genetic characterization of the virus were performed by sequencing the coding region of the structural polyprotein, with subsequent analysis of the protein structure through modeling. Phylogenetic analysis indicated that the circulating genotype in the State of Rio Grande do Norte is East-Central-South-African II (ECSA II). The comparison between CHIKV sequenced in this study and its ancestor from ECSA II lineage identified in Uganda in 1982 (GenBank: HM045812) revealed the presence of 21 non-synonymous mutations. Sequencing of serum and CSF CHIKV from the same patient revealed two non-synonymous mutations potentially associated with viral neurovirulence: N606K and P677L. In addition, the analysis of the protein model showed the circulating non-RN virus has no mutation at position A226V which is the major part of virus infection for Aedes albopictus. In conclusion, this study reveals the origin of CHIKV circulating in the State of Rio Grande do Norte and possible markers of viral neurovirulence, useful information to understand the viral evolution and the pathogenesis of the disease.